Demystifying the Science and Art of Political Polling - By Mark Blumenthal

May 10, 2006

The Latest from CBS/NYT

Another day, another very high profile poll release. Today, it's the latest from the CBS/New York Times (see NYTimes article, results; CBS article, results, Medicare results). A few quick thoughts at the end of another busy day:

The true poll junkie will want to flip back and forth between the PDF releases from CBS News and the New York Times. As always, the release from the Times has complete time series data -- that is, results on comparable questions on every CBS/NYTimes poll (and many that were done just by CBS) going back ten year or more in some cases. As always, the two CBS releases provide results for every question in the survey broken out among Democrats, Republicans and independents.

Like the USAToday/Gallup survey earlier this week, this latest CBS/New York Times survey seems to be getting more attention from the left wing of the blogosphere than the right. I discovered the new "buzz tracker" feature on Real Clear Politics last night (after a hundred or so RCP readers used it to click through to yesterday's post). They are currently listing 28 blogs commenting on the NYTimes story this morning, and after clicking through to all 28 I count 13 posts by liberal blogs, 7 by conservatives (with the rest not obviously left or right - your "mileage may vary").

The conservatives seem to be noting -- as per Reynolds, Sullivan and Kaus -- that the poll also includes less than flattering results for John Kerry and Al Gore. The favorable ratings for Kerry (26%) and Gore (2819%) are lower than for Bush (29%), although Bush's "not favorable" rating is far higher (55%) than for either Kerry (38%) or Gore (39%27%).

BullDogPundit takes his usual look at the demographics of the CBS/NYTimes sample of adults, finds it different from the exit poll of voters in 2004 and comes to his usual conclusion that this discrepancy render this "another crap poll." MP has always found this line of argument wildly unpersuasive.

The ratio of self-identified Democrats (37%) to Republicans (25%) on this survey is bit higher than on the other polls done by CBS and the Times earlier this year (I get an average of 34% Democrat, 29% Republican). However, the culprit behind the president's declining overall approval rating appears to be his support among Republicans - not the mix of Republicans and Democrats in the survey. As Franklin notes, the percentage of Republicans that approve of Bush's job rating is a point higher on the CBS/NYT poll (69%) than on the USAToday Gallup poll (68%). Another way of saying the same thing: Readjust the party percentages to match the 34%-29% party ID average on recent CBS/NYT polls, and the Bush job approval would rises only slightly (from 31% to 33%)

One reason to avoid this sort of "dynamic weighting" is that CBS/NYT, like most public polls, asks party identification last. In this case, that means the party identification question came at the end of a very long survey that went into great depth on issues (including gas prices, immigration, the war in Iraq) on which voters expressed considerable unhappiness with the president's performance. Given the evidence that party ID can change during the course of an interview, it is entirely possible that the apparent skew on this survey was a function of questions that came earlier, not an "oversampling" of Democrats relative to Republicans.

Comments

"The conservatives seem to be noting -- as per Reynolds, Sullivan and Kaus -- that the poll also includes less than flattering results for John Kerry and Al Gore. The favorable ratings for Kerry (26%) and Gore (2819%) are lower than for Bush (29%), although Bush's "not favorable" rating is far higher (55%) than for either Kerry (38%) or Gore (39%27%)."

Shouldn't you point out that comparing the president's approval numbers to those of people who aren't the president is not exactly kosher? Bush is in the news so much that even other highly ranked politicians like the senator and former vice president are not really comparable.

"Professional pollster Mark Blumenthal started Mystery Pollster to provide better interpretation of polling results and methodology... offers much needed help to Political Wire readers" - Political Wire